Keyword and tag hierarchy missing in PSE15

Adobe help restored my catalog but all of the keywords and tags are missing.

I think they did not 'restore' your catalog, otherwise you should have restored the keywords as well. I rather think they created a new catalog and re-imported your images.

You only can 'restore' from a full backup (unfortunately, yours is a bit old).

I hope you'll be able to find the corrupt catalog, which should not be overwritten by a new import.

You can find the catalogs present in your computer by searching for files named 'catalog.pse15db'. They can be in 'hidden' folders, so you have to enable viewing those hidden folders in the Explorer.

If you can find one, the folder containing that catalog.pse15db file may be the corrupt one. Check the size and date.

If you think it is the corrupt catalog folder, create a new empty folder (named 'my light catalog' or something like this). Copy the 'catalog.pse15db' file in that empty catalog and (the organizer being closed), double click on this file. That should open the organizer with this 'light' catalog. You should recover your keywords, albums etc, but not face recognition for instance. Let the organizer rebuild the missing components and thumbnails. That may take a few hours. Then please report back.